Pneumatic device



Jan. 16,1940, B, ELLWQO 2,187,114

PNEUMATIC DEVICE Filed March 51, 1938 FIG. FIG. 2

/N 1/5 N TOR W. B. ELL W000 W M/ a ATTORNEY Patented Jan. 16, 1940 UNiTED STATES PATENT orricr PNEUMATIC DEVICE Application March 31, 1938, Serial No. 199,311

1 Claim.

This invention relates to pneumatic devices and more particularly to a pneumatic trigger amplifier for use, for example, for operating a multiplicity of switching elements simultaneously 1'5 at a point remote from the power generating source.

The object of the invention is the provision of a pneumatic trigger amplifier device of the type above referred to which will be simple, positive 10 operation, and in which the force required for its operation is a small fraction of the air pressure required for the operation of the switching elements actuated thereby.

In telephone systems, for example, there are 15 conditions which require the operation of a multiplicity of switching devices simultaneously but where the space required for the mounting of a sufficiently high power motor element is not available. The present invention contemplates the g of a remotely placed source of power which is operatively connected to an actuating element disposed at the pcintof the applied force so as to avoid the damaging effects of vibrations inherent to the use of a high power motor mechanism at the point or" the applied force and the consequent improper operation of the switching devices actuated thereby, the source of motive power being, for example, controlled by a comparatively small electromagnet which may itself be controlled by a switching device placed at a remote point from the switching devices it is desired to operate.

the drawing Fig. l is a side elevation view of a switching device assembly operatively connected to the trigger device of the invention,

the operable element of such a device being shown in section.

Fig. 2 is a partial front view of Fig. 1;

3 a top view of the trigger device shown 4' with. its cover removed, and

Fig. 4 is an enlarged longitudinal sectional view taken on line of Fig. 1.

As shown in the drawing, a casing is formed of two parts and H318 (Fig. 4) each provided with a peripherally disposed rim II and 12 for clamping a gasket i l therebetween through the tightening of a plurality of screws 15 so as to form an air-tight joint between these casing portions. The casing portion ill is provided with an inwardly extending peripheral rim 16 shown in Fig. 4 for receiving a ll of relatively soft material to be clamped between the rim portion I6 and a partition it to form an air-tight closure .55 therebetween, a portion of this partition cooperating with integrally formed side walls l9 and top wall 29 to form a chamber C2, while forming in cooperation with casing portions Ill and 593 a second and a third air chambers Cl and C3, respectively.

The wall 28 of chamber C2 is provided with a so-called bleeder hole BH and an opening 2! closed by a corrugated diaphragm 22 clamped between the wall and a ring 23 by a plurality of screws 24. The casing portion ll] and one of the side walls is of chamber C2 are provided at similar disposed ends with openings 25 and 26 respectively for receiving a bushing 21 secured thereto by a nut screw 28. This bushing serves for securing one end of a tubing 29 shown in 15 Fi l which connects the chamber C2 to a suitable air compressor device, not shown, while the casing portion Ill is provided at its other end with a sleeve portion 38 for securing one end of a tubing 35 shown in Fig. 1 connecting a remotely disposed air chamber 32, this chamber being formed of a circular casing 35 having a yieldabie wall in the form of a diaphragm 33 clamped therein by a ring it engaging the interiorly screw-threaded portion of casing 35. 25

The ring 36 is formed with a cylindrical portion 31' which is screw threaded for engaging the arm 38 of a multi-switching device MS having an operating bar 35 disposed in operative relation with one of a plunger lil slidably 30 mounted in the cylindrical portion 31 of ring 36 and having its other end secured to the diaphragm 33 for operation as will be hereinafter described in detail.

' In the position shown in Fig. 1, the contacts at 35 of each set are normally closed and the contacts 1; of these sets open so that the movement of diaphragm 33 and that of plunger it actuated thereby is imparted to the bar 39 for opening the contacts at of each set and closing the con- 40 tacts g/ of these sets.

To the center portion of diaphragm 22 as shown in Fig. 4 is securely mounted a plunger ll formed with valves ii? and 43 for engaging, as the case may be, the valve seats 44 and 45 45 respectively in the partition 18 and in the easing portion ill, the plunger 4! being guided at its free end by a plug 45 having air exhaust openings 48 and 49 and threadedly engaging the cylindrical extension 4'! formed with casing por- 50 tion ID.

The partition 18 at the point between the side wall ill of air chamber 02 and the adjacent end wall of casing portion 10 is provided with an Opening 59 normally closed by a spring pressed ball 5| disposed in a tubular extension 52 itself having openings 53 and 54 connecting the air chamber Cl formed by the casing portion IDB with the air chamber C3 formed by the casing portion I6 and partition I 8 upon the automatic operation of ball 5| in a manner which will be hereinafter described in detail.

The casing portion lllB is provided with an opening 55 normally closed by a spring pressed ball 56 in a cylindrical extension 51, this extension being provided with a plurality of openings 58 connecting the air chamber CI to the atmosphere. On the casing portion IllB, as shown in Figs. 1 and 4 is mounted a bracket 59 secured thereto by screws 60 and on this bracket is mounted a relatively small electromagnet 6| provided for actuating a plunger 62 for operating the ball 56 upon the energization of this magnet to cause the operation of the trigger device in the following manner.

With the operating parts of the device in the position as shown in Figs. 1 and 4 supposing that a compressor connected to bushing 21 supplies the chamber C2 with air at a pressure sufficient for operating the bar 39 of the switchin device MS, the air from chamber C2 passes into chamber Ci through the bleeder hole BI-I in wall 20 until the pressure becomes equal in these chambers so that the diaphragm 22 does not operate since the balls 5| and 56 close the openings 5H and 55, respectively and the opening 45 is closed by valve 43. Upon the energization of electromagnet 6|, however, as effected by a remotely disposed controlling switching device (not shown), the operation of plunger 62 and thereby the movement of ball 56 from its seat 55 permits the air from chamber CI to exhaust to the atmosphere through the holes 58 and seat 55 of ball 56. Under this condition the air pressure in chambers Cl and C2 becomes unbalanced and the air pressure in chamber C2 acts on the diaphragm 22 and forces it to bulge toward the chamber C| thus operating the plunger 4| for lifting the valve 43 from its seat 45 and closing the valve 42. The air from chamber C2 now flows into chamber C3 through valve 43 and hence to chamber 32 through tubing 3| to cause the bulging operation of diaphragm 33 for operating the plunger 46 and thereby the bar 39 of the switching device for opening the contact a: and closing the contact 1/ of each set. Under this condition the ball 5| is lifted from its seat 50 due to the difference in pressure in chambers CI and C3.

Upon the deenergization of magnet 6| and the consequent closure of opening 55 by spring pressed ball 56, the ball 5| which is still raised due to the higher air pressure in chamber C3 permits the air to flow in chamber Cl until the air pressure becomes equal in these two chambers. This condition permits the return of diaphragm 22 to normal for closing the valve 43 and reopening the valve 42 to permit the air to exhaust to the atmosphere by the openings 48 and 49 in plug 46 when the diaphragm 33 returns to normal to close the contact a: and open contact 1/ of each set and the device is now ready for a subsequent switching operation which is effected as above mentioned by the closing of the contact used for controlling the energization of magnet 6| and the consequent operation of the ball 56 controlled thereby. The function of the valve formed by ball 5| and seat 50 is to provide an air path in addition to bleeder hole BH so as to permit the quick balancing of the pressure in chambers C| and C3 and thereby the return of the diaphragm 22 to normal in a minimum of time, thus reducing the amount of air escaping from the valve 42 to a minimum following the closure of opening 55 by ball 56.

In this device the time of operation depends (1) upon the air pressure, (2) the relative sizes of valve seats 44 and 45, (3) the openings 50 and 55 and BH, (4) the capacity of chambers Cl, C2 and C3 and (5) the capacity of chamber 32. High speed is obtained, however, by making the capacity of chamber C| as small as possible and making the ratio of the area of opening 55 as large as the operating force of magnet 6| will permit. The area of diaphragm 22 should be, however, several times that of openings 44 and 45 which in turn should be at least as large as the cross-section of tube 3| which should be in turn equal to that of the input air tubing connecting with bushing 21.

The device of the invention is particularly useful for operating power driven switches involving large numbers of contacts or for heavy current contacts. The intrinsic sensitivity of the device allows it to be used as a substitute for an electrical contact in connection with an electromagnetic relay and since the forces exerted by diaphragm 33 are unlimited in magnitude, it may be used to control heavy current switches or gangs of contacts, while permitting the casing to be removed from the rest of the apparatus at a distance limited only by the tubing connection between the casing and the point of the applied force.

What is claimed is:

A trigger amplifier comprising three air-tight chambers, one of said chambers having means for connection with an air pressure source, another of said air chambers having means for connection with a power applying device and the 

